Abstract
Effects of soil solarization on natural and/or artificially established populations of M. phaseolina and S. rolfsii were examined using 51-.mu.m clear polyethylene tarp for 2, 4 or 6 wk during spring, summer and fall trials. In no case was tarping effective in reducing either natural M. phaseolina populations or buried inocula to undetectable levels. Complete control of buried, precounted sclerotia of S. rolfsii was achieved to 15-cm depths in the summer but only to 1 cm in the fall.